Solids, Liquids and Gases - Change of State (Paper 2)

Question 1

why will heating a system change the energy stored within the system?

Answer 1

heating a system increases its internal energy, which can raise its temperature or, during phase changes, be used as latent heat to change its state without altering temperature. Work done on the system can also change its internal energy

Question 2

what changes of state happen when a solid is heated?

Answer 2

a solid melts into a liquid
a liquid evaporates/boils into a gas

Question 3

what changes of state happen when a gas is cooled?

Answer 3

a gas condesnes into a liquid
a liquid freezes into a solid

Question 4

what are the arrangement of particles in a solid?

Answer 4

• tightly packed
• held in fixed pattern
• vibrate about fixed positions

Question 5

what are the arrangement of particles in a liquid?

Answer 5

• tightly packed
• can slide over each other

Question 6

what are the arrangement of particles in a liquid?

Answer 6

• very spread out
• move with rapid, random motion

Question 7

how would you obtain a temperature–time graph to show the constant temperature during a change of state?

Answer 7

• remove the boiling tube of stearic acid from
  the water bath
• place the tube into a beaker of room
  temperature water
• add a separate thermometer to the water
• take readings from the thermometer in the
  stearic acid and the water every minute
• note readings
• note when you observe the stearic acid change from a liquid to a solid

Question 8

what is specific heat capacity?

Answer 8

Amount of heat energy required to increase the temperature of 1kg of a substance by 1 degree

Question 9

what is the equation for change in thermal energy?

Answer 9

change in thermal energy = mass x specific heat capacity x change in temperature

Question 10

how would you investigate the specific heat capacity of materials including water and some solids?

Answer 10

• make note of all measurements: current (A), potential difference (V), mass (kg).
• use the electronic balance to measure the mass of your water
• record the initial temperature of your water
• switch on the heater and start your stopwatch
• while the heater is switched on take readings from the Ammeter and the Voltmeter.
• use these to calculate the Thermal Energy that will be supplied to the water in 10 minutes
• record the temperature of your water after 10 minutes and calculate the change in temperature